Machine tool attachment

Abstract

A machine tool attachment which provides for material handling, positioning, and clamping during machining and also eliminates the need for custom tool fixtures is described. The machine tool attachment mechanically advances material to be machined through a tubular tail stock and into a head stock. Collets located in the tail stock and head stock automatically power clamp the material and a rotary indexer automatically rotates and indexes the material during the machining operation. Once machining is completed, the material between the head stock and tail stock is further clamped by the attachment and then cut by the machine tool. Remaining material can then be advanced by the attachment and the process repeated. The machine tool attachment interfaces with a numerically controlled machining center which transmits signals to control the functions of the attachment for proper coordination with the machine tool.

What is claimed is: 
     
       1. A machine tool attachment for positioning material for machining operations, comprising: a tail stock housing having a tubular passage therethrough;   first gripper means for gripping said material in said tail stock housing, said first gripper means coupled for rotation with said tail stock housing, said first gripper means comprising a collet and a connecting power means, said collet being axially moveable within said tubular passage by said power means such that said material can be gripped and released by virtue of the position of said collet within said tubular passage;   a head stock housing having a bore axially aligned with said tubular passage of said tail stock housing;   second gripper means for gripping said material in said head stock housing, said second gripper means coupled for rotation with said head stock housing, said second gripper means comprising a collet and a connecting power means, said collet being axially moveable within said bore by said power means such that said material can be gripped and released by virtue of the position of said collet within said bore;   advancing means for advancing material through said tail stock and into said head stock such that said material is in a machining position;   positioning means for rotating said head stock and said tail stock to sequentially position said material to perform machining operations, said positioning means including a synchronization means for synchronizing rotation of said head stock and said tail stock such that said head stock and said tail stock rotate in unison and said material is uniformly rotated; and   resilient ejecting means in said head stock housing for ejecting a material stub after said material is machined.   
     
     
       2. The machine tool attachment of claim 1 wherein said synchronizing means comprises a geared shaft coupled for rotation with said head stock and said tail stock. 
     
     
       3. The machine tool attachment as described in claim 2 wherein said positioning means comprises a powered rotary motor with indexing means to stop rotation at any circumferential point. 
     
     
       4. The machine tool attachment as described in claim 2 also including: a material guide axially aligned with said tail stock tubular passage and said head stock bore.   
     
     
       5. The machine tool attachment as described in claim 4 wherein said material is extruded or bar stock material. 
     
     
       6. The machine tool attachment as described in claim 4 wherein each of said collets is fitted with an insert jaw designed to fit said material. 
     
     
       7. The machine tool attachment as described in claims 4 or 6 wherein said advancing means comprises a clamping means for clamping said material and an actuation means for longitudinally moving said clamping means such that said material is advanced. 
     
     
       8. The machine tool attachment of claim 7 wherein said clamping means comprises a guide rod, two opposed clamping members pivotally mounted to said guide rod, and means for simultaneously rotating said clamping members such that said material is either clamped between said clamping members or released from said clamping members, said clamping members being longitudinally moveable along said guide rod for advancing said material. 
     
     
       9. The machine tool attachment of claim 8 wherein said means for simultaneously rotating said clamping members is a double acting piston assembly. 
     
     
       10. The machine tool attachment of claim 4 wherein said actuation means for longitudinally moving said clamping means comprises a piston assembly, whereby movement of the piston of said piston assembly results in the corresponding longitudinal movement of the material.